Explosion proof fluorescent lighting unit



May 28, 1957 R. F. LESTER 2,794,113

EXPLOSION PROOF FLUORESCENT LIGHTING UNIT Filed Sept. 23, 1955 3 Sheets-Sheet 1 I N VEN TOR.

Ray E Lest? ATTORNEY.

May 28, 1957 R. F. LESTER EXPLOSION PROOF FLUORESCENT LIGHTING UNIT Filed Sept. 25. 1955 3 Sheets-Sheet 2 RH vn w 5 N5 N w m m n F A M y 8, 1957 R. F. LESTER 2,794,113

EXPLOSION PROOF FLUORESCENT LIGHTING UNIT Filed Sept. 23, 1955 3 Sheets-Sheet 3 J E j u I-NVENTOR.

RciyELesteF ATTa y,

United States Patent Office 2,794,113 EXPLOSION PROOF FtjIiglgREsCENT LIGHTING Lester, Syracuse, N. Y., assignor to Grouse-Hinds Ray F. I

a corporation of New York This invention has to do with a fluorescent tube lighting unit and in particular with a lighting unit embodying a plurality of fluorescent tube housings mounted on a carriage, provided with ground wheels, whereby the carriage can be conveniently moved about. The unit is intended particularly for use in hazardous locations, such as airplane hangers for illuminating the under side of the fuselage and wings while the plane is being worked on.

The invention has as an object a fluorescent lighting unit of the general type referred to embodying a plurality of explosion proof fluorescent tube housings, and an explosion proof ballast housing, these housings being assembled as a unit which is adjustable about a horizontal axis to direct the light emitted from the unit on the desired portion of the plane.

The invention consists in the novel features and in the combinations and constructions hereinafter set forth and claimed.

In describing this invention, reference is had to the accompanying drawings in which like characters designate corresponding parts in all the views.

In the drawings:

Figure l is an end elevational view of a lighting unit embodying my invention.

Figure 2 is a side elevational view of the unit with parts in section.

Figure 3 is a view corresponding to line 33, Figure 2.

The unit is mounted upon a carriage structure having side rails 10 and end rails 11 forming a rectangular arrangement supported on a plurality-in this instance four, ground wheels 12, whereby the unit may be conveniently moved about the floor area of the airplane hanger. The carriage is formed with an upwardly extending support at each end consisting of inclined brace members 13, secured to a horizontally extending portion 14 at their upper ends. Each of the horizontal portions 14 is provided with a bearing block 15 having a removable cap 16. The bearing members 15, 16, are employed to support a frame consisting of cross members 18 secured to uprights 19 which, in turn, are secured at their upper ends to transversely extending pieces 20 afiixed to side members 21. The members 18 are provided with trunnions 24 journalled in the bearings 15, the cap portions 16 of which are held in position by bolts 25, one of which is provided with a thumb nut 27. The frame is movable about the horizontal axis of the trunnions 24, and is maintained in adjusted position by tightening thethumb nuts 27. The members 19 extend downwardly from the trunnions 24 and are bent inwardly, as at 28. These horizontally bent end portions 28 have plates 30 mounted thereon.

The lighting unit includes a plurality of explosion proof fluorescent tube housings-in this instance three. Each of these housings consists of a glass tube 30 to one end of which a hollow metallic casting 31 is aflixed, and to the opposite end there is aflixed a hollow metallic casting 32. The end castings 31 are formed on their upper sides with a circumferentially extending recess, in which a cross member 35 is positioned, and these housings are Patented May 28, 1957 formed with a depending portion 36 having a threaded aperture to receive one end of a connecting nipple 37, the opposite end of which is threaded into a cap 38.

The ballast for the fluorescent tubes is mounted in a ballast housing having a cylindrical portion 40, threaded at one end into a cast metal housing 41, which is formed with a hollow arm portion 42, the upper wall 43 of which is formed with three pads on which the caps 38 are mounted in flame tight relation, as by screws 44. The casting 41 is also formed at its lower side with a hub 46 g in which the stem of a foot piece 47 is threaded. This foot piece is mounted on and secured to one of the plates 30, as by screws 48.

The end castings 32 of the fluorescent tube housings are of circular form, having a flat boss 50 on their under sides, these bosses being mounted upon a cross channel member 51 supported by a fitting 52 through links 53. The fitting 52 is supported by a foot piece 54 through a nipple 55. The foot piece 54 is mounted upon the rear cross plate 30, see Figure 2. The fitting 52 is connected to the inner end of the cylindrical member 40 by a tube or rod 54. In this manner, the fluorescent tube housings are supported so that they extend parallel with the axis of the trunnions 24, the end castings 31 being supported by the ballast housing.

The hollow arm portion 42 of the ballast housing is formed with one or more internally threaded hubs 56, to which the supply cable is connected. The fluorescent tube receptacles 58, mounted in the end castings 31, are connected to the ballast by conductors 59 which extend through the nipples 37 and caps 38, and to the hollow arm structure 42, which is common to all of the tube housings, see Figure 3. After this wiring is installed, the caps 38 are filled with sealing material 60 to form a flame tight joint between the ballast housing and the fluorescent tube housings. The tube receptacles, mounted in the end castings 32, are connected by conductors extending through conduits 61 extending between the castings 31, 32, and connected thereto in flame tight relation. The castings 31 are provided with plug closures 63, and the castings 62 with similar closures 64, these closures being removable for replacing the fluorescent tubes. A reflector 66 is secured to the tubes 61, as by clips 67, this reflector having a flat central portion extending below the tubes 30 and curving upwardly at its side edges, see Figures 1 and 3, whereby the reflector is common to all of the tube housings. A shield 68 of infrangible light transmitting mate rial is detachably secured to the side rails 21 of the frame, this serving to prevent damage to the tubes 30 by falling objects and the like.

It will be apparent that the unit is readily portable and can be adjusted to direct the light emitted therefrom to any desired location. The unit is explosion proof and can therefore be used advantageously in hazardous locations.

What I claim is:

1. An explosion proof fluorescent lighting unit comprising a carriage having ground wheels, a support member extending upwardly at each end of said carriage, a frame mounted between said supporting members and being journalled thereon for movement about a horizontal axis, a plurality of explosion proof fluorescent tube housings mounted in side by side relation in said frame, a ballast housing mounted in said movable frame and being rigidly connected to each of said tube housings in flame tight relation therewith, an arcuate shield formed of light transmitting material mounted on said frame above said tube housings and forming a protective canopy thereover, and reflector means supported by said tube housings on the opposite side thereof from said shield and being operable to direct the light therefrom through said shield.

2. An explosion proof fluorescent lighting unit for airplane hangers and the like comprising a carriage having ground wheels for movement of the unit about the floor of the hanger, a support member extending upwardly at each end of the carriage, a rectangular frame mounted between said supporting members and being journalled thereon for movement about a horizontal axis, means operable to secure said frame in adjusted position, a plurality of explosion proof fluorescent tube housings mounted in side by side relation in said frame and extending parallel to said axis, a ballast housing mounted on the movable frame below said tube housings, conduit means forming a flame tight connection between said ballast housing and each of said tube housings, an arcuate shield formed of infrangible light transmitting material mounted on said frame above said tube housings and forming a protective canopy 'thereover, and a substantially U-shaped reflector secured to the under side of said tube housings and being operable to direct the light therefrom through said shield.

References Cited in the file of this patent UNITED STATES PATENTS 973,685. Moore Oct. 25, 1910 1,432,659 Bochet Oct. 17, 1922 1,850,598 Mills et a1 Mar. 22, 1932 2,360,420 Hill Oct. 17, 1944 FOREIGN PATENTS 988,491 France Aug. 28, 1951 

